Backlight unit and video display apparatus applying the same therein

Abstract

A backlight unit of thin-type comprises: at least one or more light source(s); plural numbers of light guide plates, each of which is configured to guide and irradiate the light of the light source(s) to a side of a liquid crystal panel; and a chassis, on which the light source(s) and the light guide plates are fixed, thereby being constructed by aligning the light guide plates, wherein the following conditions are satisfied: 15.0 mm>h, 20 °≦θ≦ 60 ° when assuming that a distance from an irradiation surface of the backlight unit to the light guide plate is “h”, and that an angle indicative of a half-value light intensity of a light emitting from a light emission surface of the light guide plate, thereby providing a video of high picture quality, and there is also provided a video display apparatus applying the same therein.

1. A backlight unit, comprising:
 at least one or more light source(s); 
 plural numbers of light guide plates, each of which is configured to guide and irradiate the light of said light source(s) to a side of a liquid crystal panel; and 
 a chassis, on which said light source(s) and said light guide plates are fixed, thereby being constructed by aligning said light guide plates, wherein 
 the following conditions are satisfied:
   15.0 mm>h, 20°≦θ≦60°
 
 
 when assuming that a distance from an irradiation surface of said backlight unit to said light guide plate is “h”, and that an angle indicative of a half-value light intensity of a light emitting from a light emission surface of said light guide plate. 
 
     
     
       2. The backlight unit, as described in the  claim 1 , wherein said plural numbers of light guide plates are constructed in one body, being continuous in a first direction, or a second direction perpendicular to said first direction, or a direction combining said first direction and said second direction. 
     
     
       3. The backlight unit, as described in the  claim 1 , further comprising an optical member, being disposed on a light emission side of said light guide plate, which is configured to receive and diffuse the light from said light guide plate, and the irradiation surface of said backlight unit is an light incident surface of said optical member. 
     
     
       4. A backlight unit, comprising:
 at least one or more light source(s); 
 plural numbers of light guide plates, each of which is configured to guide and irradiate the light of said light source(s) to a side of a liquid crystal panel; and 
 a chassis, on which said light source(s) and said light guide plates are fixed, thereby being constructed by aligning said light guide plates, wherein 
 the following conditions are satisfied:
   15.0 mm>h, 
 
 when assuming that a length from a light incident portion of said light guide plate to an end portion thereof is “L”, width of said light guide plate is “W”, and a distance from an irradiation surface of said backlight unit to said light guide plate is “h”, and further,
   0.1≦I≦0.6
 
 
 where “I” is a light intensity at each of points separating from a center of a certain light guide plate by distance “L” in a direction to a neighboring light guide plate and separating by distance “W” in a direction perpendicular to that direction, and when assuming that a central brightness of said certain light guide plate is 1. 
 
     
     
       5. The backlight unit, as described in the  claim 4 , wherein said plural numbers of light guide plates are constructed in one body, being continuous in a first direction, or a second direction perpendicular to said first direction, or a direction combining said first direction and said second direction. 
     
     
       6. The backlight unit, as described in the  claim 4 , further comprising an optical member, being disposed on a light emission side of said light guide plate, which is configured to receive and diffuse the light from said light guide plate, and the irradiation surface of said backlight unit is an light incident surface of said optical member. 
     
     
       7. The backlight unit, as described in the  claim 5 , wherein said light guide plate has a miniature light reflection element for guiding the light from said light source within a predetermined range of angles in a light emission surface of said light guide plate. 
     
     
       8. The backlight unit, as described in the  claim 7 , wherein said miniature light reflection element is a prism, a micro-lens, a fine frustum of a cone, concave-convex grooves, or a blast forming surface. 
     
     
       9. A video display apparatus, installing the backlight unit described in the  claim 1 , and combining a liquid crystal panel, an electric power circuit, a signal processing circuit, and a structure therewith. 
     
     
       10. A video display apparatus, installing the backlight unit described in the  claim 4 , and combining a liquid crystal panel, an electric power circuit, a signal processing circuit, and a structure therewith.